Question

我正在尝试启动带有警报的活动。 PendingIntent启动接收器，接收器启动活动。我当前的问题是活动从后台开始，无法听到警报声。较旧的SO问题中的大多数标志对于Oreo和较新的设备均已弃用。有谁有很好的方法来处理这个问题？

提前谢谢

警报创建：

alarmManager.setExact(AlarmManager.RTC_WAKEUP, intervalFinished, pendingIntent)

接收器

class OnAlarmReceiver : BroadcastReceiver() {

    override fun onReceive(context: Context, intent: Intent) {
        val intent = Intent(context, AlarmActivity::class.java)
        intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK)

        context.startActivity(intent)
    }
}

活动：

private var wake: PowerManager.WakeLock? = null

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    val powerManager = getSystemService(Context.POWER_SERVICE) as PowerManager
    wake = powerManager.newWakeLock(PowerManager.FULL_WAKE_LOCK
            or PowerManager.ACQUIRE_CAUSES_WAKEUP, "App:wakeuptag")
    wake?.acquire(10*60*1000L /*10 minutes*/)

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O_MR1) {
        setShowWhenLocked(true)
        setTurnScreenOn(true)
    } else {
        window.addFlags(WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED
                or WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD
                or WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON
                or WindowManager.LayoutParams.FLAG_TURN_SCREEN_ON
                or WindowManager.LayoutParams.FLAG_ALLOW_LOCK_WHILE_SCREEN_ON)
    }
    setContentView(R.layout.activity_layout)
}

override fun onPause() {
    super.onPause()
    if(wake != null && wake!!.isHeld){
        wake!!.release()
    }
}

Answer 1

您应该在自己的AndroidManifest.xml中

<activity
    android:name=".AlarmActivity"
    android:showOnLockScreen="true"
    android:turnScreenOn="true"/>

以下检查也应在 setContentView（）之后。由于在您添加标志时，没有可以使用它们的视图。

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O_MR1) {
    setShowWhenLocked(true)
    setTurnScreenOn(true)
} else {
    window.addFlags(WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED
           or WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD
           or WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON
           or WindowManager.LayoutParams.FLAG_TURN_SCREEN_ON
           or WindowManager.LayoutParams.FLAG_ALLOW_LOCK_WHILE_SCREEN_ON)
}

即使关闭屏幕也可以开始活动

1 个答案: